package com.zhuang.io.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;

public class Server {
	public static void main(String[] args) throws IOException {
		// 1. 获取通道
		ServerSocketChannel ssChannel = ServerSocketChannel.open();
		// 2. 切换非阻塞模式
		ssChannel.configureBlocking(false);
		// 3. 绑定连接
		ssChannel.bind(new InetSocketAddress(9999));
		// 4. 获取选择器
		Selector selector = Selector.open();
		// 5. 将通道注册到选择器上, 并且指定“监听接收事件”
		ssChannel.register(selector, SelectionKey.OP_ACCEPT);
		// 6. 轮询式的获取选择器上已经“准备就绪”的事件
		while (selector.select() > 0) {
			System.out.println("轮一轮");
			// 7. 获取当前选择器中所有注册的“选择键(已就绪的监听事件)”
			Iterator<SelectionKey> it = selector.selectedKeys().iterator();
			while (it.hasNext()) {
				// 8. 获取准备“就绪”的是事件
				SelectionKey sk = it.next();
				// 9. 判断具体是什么事件准备就绪
				if (sk.isAcceptable()) {
					// 10. 若“接收就绪”，获取客户端连接
					SocketChannel sChannel = ssChannel.accept();
					// 11. 切换非阻塞模式
					sChannel.configureBlocking(false);
					// 12. 将该通道注册到选择器上
					sChannel.register(selector, SelectionKey.OP_READ);
				} else if (sk.isReadable()) {
					// 13. 获取当前选择器上“读就绪”状态的通道
					SocketChannel sChannel = (SocketChannel) sk.channel();
					// 14. 读取数据
					ByteBuffer buf = ByteBuffer.allocate(1024);
					int len = 0;
					while ((len = sChannel.read(buf)) > 0) {
						buf.flip();
						System.out.println(new String(buf.array(), 0, len));
						buf.clear();
					}
				}
				// 15. 取消选择键 SelectionKey
				it.remove();
			}
		}
	}
}
